Sea smarts

Scientists studying mollusks discover there is more than one way to make a brain

By John Pastor

Leonid Moroz

Seemingly simple animals such as the snail and squid have ransacked the genetic toolkit over the last half billion years to find different ways to build complex brains, nervous systems and shells, according to an international team of researchers, including a neuroscientist with the UF Whitney Laboratory for Marine Bioscience.

Using genomics and computational approaches, the scientists reconstructed the evolutionary history of the entire phylum Mollusca, which includes more than 100,000 living species, ranging from giant squid to microscopic marine worm-like creatures.

One of the surprising outcomes of the study, recently published online in Nature, suggests that the formation of a complex brain in mollusks has independently occurred at least four times during the course of evolution — a finding that may prove useful to regenerative medicine scientists trying to develop new ways to help people with degenerative brain diseases.

“Nature did many experiments for us over the past 500 million years, using different molecular tools to build complex brains by independently centralizing smaller neuronal structures,” said Leonid L. Moroz, Ph.D., a member of the department of neuroscience with the UF College of Medicine. “The octopus, for example, is very intelligent. It can learn by watching, and it has one of the most complicated brains of any animal without a backbone. And it evolved completely independently from us, using different genes, gene regulators and, in part, different neuronal signaling molecules.”

By looking at the genomic data, the scientists were able to better understand the relationships between aplacophorans, which are worm-like creatures; gastropods, which include slugs and snails; cephalopods, such as octopuses and squids; and a variety of other shell-producing creatures.